The conventional diagnosis challenge: Real-time PCR and nested PCR correlation with the scoring system for individuals at high-risk of Pneumocystis jirovecii pneumonia

Introduction. Pneumocystis jirovecii is an opportunistic fungus that affects mainly people living with HIV (CD4 cell count lower than 200 cells/ml) and other immunosuppressed patients. Since P. jirovecii does not grow on routine mycological media, diagnosis of P. jirovecii pneumonia relies on indirect evidence of its presence in respiratory samples. Objectives. To associate the results of direct immunofluorescence and two molecular methods with a score to predict P. jirovecii pneumonia in patients with AIDS. Materials and methods. A prospective study was conducted with 40 patients. A respiratory sample collected before treatment was subjected to direct immunofluorescence using the Merifluor kit, to nested PCR targeting the mitochondrial large subunit ribosomal RNA, and to the VIASURE real-time PCR kit. Results. These three techniques revealed P. jirovecii in 6, 12, and 15 samples, respectively. All positive samples by direct immunofluorescence were positive by nested PCR, and all positive samples by nested PCR amplified by real-time PCR. There was a statistically significant association between the P. jirovecii pneumonia score and the molecular methods. Two patients were early diagnosed and responded well to treatment. Conclusion. Molecular methods, especially real-time PCR, are recommended for early diagnosis of P. jirovecii pneumonia in AIDS patients.

Introducción. Pneumocystis jirovecii es un hongo oportunista que afecta principalmente a personas con HIV (recuento de CD4 menor de 200 células/ml) y a otros pacientes inmunosuprimidos. Como P. jirovecii no crece en los medios micológicos de rutina, el diagnóstico de neumonía por P. jirovecii se basa en la evidencia presente en muestras respiratorias. Objetivos. Asociar los resultados de la inmunofluorescencia directa y los de dos métodos moleculares con un puntaje para predecir la neumonía causada por P. jirovecii en pacientes con sida. Materiales y métodos. Se realizó un estudio prospectivo de 40 pacientes. Se recolectó una muestra respiratoria antes del inicio de tratamiento y se sometió a una prueba de inmunofluorescencia directa con el kit Merifluor, una PCR anidada para la amplificación de la subunidad larga del ribosoma mitocondrial y una PCR en tiempo real usando el kit VIASURE. Resultados. Estas tres técnicas evidenciaron la presencia de P. jirovecii en 6, 12 y 15 muestras, respectivamente. Todas las muestras positivas por inmunofluorescencia directa fueron positivas en la PCR anidada y todas las muestras positivas en la PCR anidada amplificaron por PCR en tiempo real. Se encontró una asociación estadística entre los valores de la neumonía causada por P. jirovecii y los métodos moleculares. Dos pacientes con diagnóstico temprano respondieron satisfactoriamente al tratamiento. Conclusión. Se recomiendan los métodos moleculares, especialmente la PCR en tiempo real, para el diagnóstico temprano de neumonía causada por P. jirovecii en pacientes con sida.

Systemic disease in leukocytoclastic vasculitis: a focus on direct immunofluorescence findings

Abstract Background Direct immunofluorescence (DIF) panels are usually ordered for clinically suspected cutaneous vasculitis, but their positivity rate is variable, and their prognostic significance is not clear to date. Objective The study aims to investigate the systemic involvement rate in leukocytoclastic vasculitis (LCV) patients and the potential clinical and laboratory associations with systemic involvement, including DIF findings. Methods A retrospective study of patients with histopathologically proven cutaneous LCV examined in the dermatology department between 2013 and 2017 was performed. Results Of the 81 patients (mean age, 50.6 years), 42 (52%) were male. The mean time between the appearance of skin lesions and biopsy was 23.1 days, ranging from 2 to 180 days. DIF showed overall positivity of 90.1%, and C3 was the most frequent immunoreactant (82.7%). Any kind of extracutaneous involvement was present in 47 (58%) of patients, with renal involvement being the most frequent (53.1%), followed by articular (18.5%) and gastrointestinal (11.1%) involvement. The presence of renal disease was associated with the detection of IgG in the lesional skin (p = 0.017), and with the absence of IgM in the lesional skin (p = 0.032). There was a significant association between C3 deposition and joint involvement (p = 0.05). Study limitations This is a single-center study with a retrospective design. Conclusion DIF seems to be a useful ancillary diagnostic tool in the evaluation of cutaneous vasculitis, but the relationship between DIF findings and systemic involvement needs to be further elucidated due to contradictory data in the current literature.

Evaluación de tres pruebas serológicas para la detección de anticuerpos contra el virus linfotrópico T humano tipo 1 (HTLV-1)

Introducción: El Perú es endémico al virus linfotrópico T humano tipo 1 (HTLV-1), por esas razones es importante conocer la fiabilidad de las pruebas diagnósticas que se usan en el país, con la finalidad de continuar o no su uso. El objetivo fue evaluar el rendimiento de tres pruebas serológicas ELISA Murex, ELISA Wantai e IFI INS-Perú para la detección de anticuerpos anti HTLV-1 frente a muestras peruanas. El estudio. Las tres pruebas fueron evaluadas frente a 382 sueros: 215 positivos y 167 negativos a HTLV-1 (Gold Standar: inmunoblot). Hallazgos. IFI no presentó falsos positivos, Wantai tuvo más falsos negativos (siete) y Murex más falsos positivos (ocho). Las tres pruebas mostraron resultados superiores a 95% para los parámetros estimados de exactitud diagnóstica. Conclusiones. IFI INS-Perú y ELISA Murex tuvieron buen rendimiento diagnóstico para la detección de anticuerpos contra HTLV-1 y son buenos candidatos para continuar siendo usados en Perú.

Background: Peru is endemic to the human T-lymphotropic virus type 1 (HTLV-1), for these reasons it is important to know the reliability of the diagnostic tests used in the country, in order to continue their use or not. The objective was to evaluate the performance of three serological tests ELISA Murex, ELISA Wantai and IFI INS-Peru for the detection of anti-HTLV-1 antibodies against Peruvian samples. The study. The three tests were evaluated against 382 sera: 215 positive and 167 negative for HTLV-1 (Gold Standard: immunoblot). Findings. IFI had no false positives, Wantai had more false negatives (seven) and Murex more false positives (eight). The three tests showed results above 95% for the estimated parameters of diagnostic accuracy. Conclusions. IIF INS-Perú and ELISA Murex had good diagnostic performance for the detection of antibodies against HTLV-1 and are good candidates to continue being used in Peru.

Analysis of Nerve Endings in the Superior Labrum-Biceps Complex by Fluorescence Immunohistochemistry and Confocal Laser Microscopy / Análise de terminações nervosas no complexo labrum-bíceps superior usando imunohistoquímica de fluorescência e microscopia a laser confocal

Abstract Objectives The capsuloligamentous structures of the shoulder work as static stabilizers, together with the biceps and rotator cuff muscles, increasing the contact surface of the glenoid cavity. Free nerve endings and mechanoreceptors have been identified in the shoulder; however, there are a few studies that describe the presence of these nerves in the biceps' insertion. The present study aimed to describe the morphology and distribution of nerve endings using immunofluorescence with protein gene product 9.5 (PGP 9.5) and confocal microscopy. Methods Six labrum-biceps complexes from six fresh-frozen cadavers were studied. The specimens were coronally cut and prepared using the immunofluorescence technique. In both hematoxylin and eosin (H&E) and immunofluorescence, the organization of the connective tissue with parallel collagen fibers was described. Results In the H&E study, vascular structures and some nerve structures were visualized, which were identified by the elongated presence of the nerve cell. All specimens analyzed with immunofluorescence and confocal microscopy demonstrated poor occurrence of morphotypes of sensory corpuscles and free nerve endings. We identified free nerve endings located in the labrum and in the bicipital insertion, and sparse nerve endings along the tendon. Corpuscular endings with fusiform, cuneiform, and oval aspect were identified in the tendon. Conclusion These findings support the hypothesis that the generation of pain in the superior labral tear from Anterior to posterior (SLAP) lesions derives from the more proximal part of the long biceps cord and even more from the upper labrum. Future quantitative studies with a larger number of specimens may provide more information on these sensory systems.

Resumo Objetivos As estruturas capsulo-ligamentares do ombro funcionam como estabilizadores estáticos, juntamente com os músculos do bíceps e do manguito rotador, aumentando a superfície de contato da cavidade glenoide. Terminações nervosas livres e mecanorreceptores foram identificados no ombro; no entanto, existem alguns estudos que descrevem a presença desses nervos na inserção do bíceps. Este estudo teve como objetivo descrever a morfologia e distribuição de terminações nervosas utilizando imunofluorescência com protein gene product 9.5 (PGP 9.5) e microscopia confocal. Métodos Foram estudados seis complexos labrum-bíceps de seis cadáveres congelados frescos. Os espécimes foram cortados coronalmente e preparados pelo método de imunofluorescência. Tanto em hematoxilina e eosina (H&E) quanto em imunofluorescência, foi descrita a organização do tecido conjuntivo com fibras paralelas de colágeno. Resultados No estudo de H&E, foram visualizadas estruturas vasculares e algumas estruturas nervosas, que foram identificadas pela presença alongada da célula nervosa. Todas as amostras analisadas com imunofluorescência e microscopia confocal demonstraram baixa ocorrência de morfotipos de corpúsculos sensoriais e terminações nervosas livres. Identificamos terminações nervosas livres localizadas no labrum, inserção bicipital e terminações nervosas esparsas ao longo do tendão. Terminais corpusculares com aspecto fusiforme, cuneiforme e oval foram identificados no tendão. Conclusão Esses achados corroboram a hipótese de que a geração de dor nas lesões labrais superiores de anterior a posterior (SLAP, na sigla em inglês) deriva da parte mais proximal do cabo longo do bíceps e ainda mais do labrum superior. Estudos quantitativos futuros com um número maior de espécimes podem fornecer mais informações sobre esses sistemas sensoriais.

Evaluation of the value of indirect immunofluorescence on salt-split skin in the diagnosis of bullous pemphigoid / 中华皮肤科杂志

Objective:To evaluate the value of indirect immunofluorescence on salt-split skin (IIF-SSS) in the diagnosis of bullous pemphigoid (BP) .Methods:A single-center clinical retrospective study was conducted. Totally, 163 patients with newly diagnosed BP were collected from Hospital of Dermatology, Chinese Academy of Medical Sciences from January 2013 to January 2019, so were 404 controls, including 161 with pemphigus, 67 with eczema, 26 with drug eruption, 23 with erythema multiforme, 18 with prurigo nodularis, etc. Blood samples were collected before the treatment, and IIF-SSS, BP180 NC16A enzyme-linked immunosorbent assay (ELISA) and direct immunofluorescence (DIF) assay were performed to evaluate the value of IIF-SSS in the diagnosis of BP. Measurement data were compared by using t test and Mann-Whitney test, and enumeration data were compared by using chi-square test and Fisher′s exact test or McNemar test. Results:The number of cases positive for IIF-SSS, BP180 NC16A ELISA and DIF assay was 160, 153 and 127 respectively in the BP group, and 0, 18 and 26 respectively in the control group. The sensitivities of IIF-SSS, BP180 NC16A ELISA and DIF assay for the diagnosis of BP were 98.15%, 93.86% and 77.91% respectively, and their specificities were 100%, 95.54% and 93.56% respectively. There was strong consistency in the diagnosis of BP between IIF-SSS and DIF (Kappa coefficient= 0.767, P < 0.001) . Conclusion:IIF-SSS has relatively high sensitivity and specificity for the diagnosis of BP, and can serve as a routine method for diagnosing BP.

Optimization of indirect immunofluorescence on salt-split skin and its application in detection of bullous pemphigoid antibodies / 中华皮肤科杂志

Objective:To optimize indirect immunofluorescence on salt-split skin (IIF-SSS), and to evaluate its performance in detection of bullous pemphigoid (BP) antibodies.Methods:Normal human foreskin and non-foreskin skin tissues were used to prepare salt-split substrates under 3 different experimental conditions: traditional group rotated at 4 ℃ for 48 - 72 hours, low-temperature immersion group soaked at 4 ℃ for 48 - 72 hours, room-temperature immersion group soaked at 25 ℃ (range: 23 - 27 ℃) for 24 hours. Serum samples were obtained from 20 patients with bullous pemphigoid (BP) in Hospital of Dermatology, Chinese Academy of Medical Sciences between August 2019 and August 2020, and subjected to IIF on the intact skin or salt-split substrates by using a multiple dilution method. Paired-sample t test was used for comparisons of means between two paired samples. Results:No dermal-epidermal separation was observed in the substrates prepared in the low-temperature immersion group at 48 - 72 hours, while dermal-epidermal separation occurred in the lower lamina lucida of the foreskin and non-foreskin substrates in the room-temperature immersion group and the traditional group. For the 20 patients with BP, the reciprocal end-point titers ( M[ Q1, Q3]) detected with the salt-split non-foreskin skin and salt-split foreskin in the room-temperature immersion group, and with the salt-split non-foreskin skin in the traditional group were 5 120 (2 560, 17 920), 1 280 (640, 2 560), 1 280 (640, 2 560), respectively. Moreover, 19 (95%) patients with BP showed that the reciprocal end-point titers detected with the substrates in the room-temperature immersion group were 1 - 5 times those in the traditional group ( t = 8.04, P<0.001), suggesting that the performance of salt-split skin in the room-temperature immersion group was superior to that in the traditional group in the detection of BP antibodies; however, there was no significant difference in the reciprocal end-point titers of BP antibodies between the salt-split foreskin in the room-temperature immersion group and salt-split non-foreskin skin in the traditional group ( t<0.001, P>0.05). The reciprocal end-point titers in 20 BP sera detected by conventional IIF on the intact non-foreskin skin and foreskin were 320 (160, 640) and 480 (160, 1 120), respectively; the reciprocal end-point titers detected by IIF on the salt-split foreskin and non-foreskin skin in the room-temperature immersion group, as well as on the salt-split non-foreskin skin in the traditional group, were all consistent with or 1 - 7 times higher than those detected by conventional IIF ( t = 6.47, 14.83, 5.26, respectively, all P<0.001) . Conclusion:The soaking method at room temperature 25 ℃ (23 - 27 ℃) for preparing salt-split substrates has advantages of short duration and simple procedure, and the sensitivity of IIF-SSS using the substrates prepared by this method is equal or superior to the traditional salt-split method for detecting BP antibodies.

Nonbullous pemphigoid / 中华皮肤科杂志

Nonbullous pemphigoid (NBP) , which is related to bullous pemphigoid, has various clinical manifestations, and is frequently accompanied by itching. Typical clinical manifestations of bullous pemphigoid (BP) , such as tense blisters or bullae, are absent in NBP cases. It is easy to misdiagnose. Histopathological findings are not specific, and its diagnosis should be confirmed by direct immunofluo-rescence, indirect immunofluorescence or salt-split indirect immunofluorescence. NBP may develop into BP in some cases, and the prognosis of NBP is better than that of BP. However, delayed diagnosis usually leads to a relatively high dosage of drugs for disease control, and a high rate of adverse reactions.

Clinical and immunoserological features of 7 cases of anti-p200 pemphigoid / 中华皮肤科杂志

Objective:To analyze clinical and immunoserological features of patients with anti-p200 pemphigoid.Methods:Clinical data were collected from patients with confirmed anti-p200 pemphigoid in Hospital of Dermatology, Chinese Academy of Medical Sciences from January 2015 to October 2021, and their clinical and immunoserological characteristics were retrospectively analyzed.Results:Seven patients with anti-p200 pemphigoid were included. Indirect immunofluorescence on salt-split skin (IIF-SSS) showed that serum IgG antibodies of the 7 patients were located in the dermis of the salt-split skin, and Western blot analysis with dermal extracts as substrates revealed a protein band with a relative molecular mass of 200 000. Four patients presented with classic bullous pemphigoid-like skin lesions, 2 initially presented with eczematous lesions, and 1 presented with linear IgA bullous dermatosis-like skin lesions. Circulating IgG antibodies could recognize the recombinant laminin γ1 C-terminal region in 6 cases. Four patients received different doses of systemic glucocorticoids, 1 of whom was resistant to high-dose systemic glucocorticoids (equivalent to 1.4 mg·kg -1·d -1 prednisone) ; 2 responded well to minocycline and dapsone; 1 was lost to follow-up. Four patients achieved complete remission and discontinued the treatment at a mean follow-up of 22.5 months; 2 received complete remissiona on minimal therapy at a mean follow-up of 8 months. Conclusion:Patients with anti-p200 pemphigoid presented with heterogeneous clinical manifestations, and the recombinant C-terminal fragment of laminin γ1 can serve as a reliable antigen substrate for the detection of autoantibodies in patients with anti-p200 pemphigoid; some patients can eventually achieve complete remission off treatment.

Non-lupus full-house nephropathy: a case series / Nefropatia "full-house" não relacionada ao lúpus: uma série de casos

Abstract Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune inflammatory disease. However, some patients may exhibit a histological pattern of kidney injury, with characteristics indistinguishable from lupus nephritis, but without presenting any extrarenal symptoms or serologies suggestive of SLE. Such involvement has recently been called non-lupus full-house nephropathy. The objective is to report a series of clinical cases referred to the Laboratory of the Federal University of Maranhão that received the diagnosis of "full-house" nephropathy unrelated to lupus, upon immunofluorescence and to discuss its evolution and outcomes. Non-lupus full-house nephropathy represents a diagnostic and therapeutic challenge, because it is a new entity, which still needs further studies and may be the initial manifestation of SLE, isolated manifestation of SLE or a new pathology unrelated to SLE.

Resumo O lúpus eritematoso sistêmico (LES) é uma doença inflamatória crônica autoimune multissistêmica. Alguns pacientes, contudo, podem exibir um padrão histológico de lesão renal, com características indistinguíveis da nefrite lúpica, porém sem apresentar quaisquer sintomas extrarrenais ou sorologias sugestivas de LES. Tal acometimento tem sido recentemente denominado nefropatia "full-house" não relacionada ao lúpus. O objetivo é relatar uma série de casos clínicos encaminhados ao Laboratório da Universidade Federal do Maranhão que receberam o diagnóstico de nefropatia "full-house" não relacionada ao lúpus à imunofluorescência e discutir sua evolução e desfechos. A nefropatia "full-house" não relacionada ao lúpus representa um desafio diagnóstico e terapêutico por ser uma entidade nova, que ainda necessita de maiores estudos e pode ser a manifestação inicial do LES, manifestação isolada do LES ou uma patologia nova não relacionada ao LES.

Virus respiratorios y características clínico-epidemiológicas en los episodios de infección respiratoria aguda / Respiratory viruses and clinical- epidemiological characteristics in episodes of acute respiratory infection

RESUMEN Con el objetivo de determinar la frecuencia viral y las características clínico-epidemiológicas en los episodios de infección respiratoria aguda de pacientes del Instituto Nacional de Salud del Niño San Borja en Lima, se analizó la información de los episodios de pacientes que requirieron al menos una prueba de inmunofluorescencia directa desde el 1 de enero del 2017 al 31 de diciembre del 2018. Se identificaron 1153 episodios en 707 pacientes. La mediana de la edad fue de 1 año y el 55% fueron del sexo masculino. La frecuencia viral fue del 13,4%; el virus respiratorio sincitial se identificó en el 10,7% de los episodios. La frecuencia viral fue mayor en los menores de 1 año (16,2%); en aquellos con enfermedad congénita respiratoria (38,9%) y durante el otoño (24,2%). Los síntomas más comunes fueron tos (70,3%) y fiebre (53,4%); y los principales diagnósticos fueron neumonía viral (31,8%) y bronquiolitis (23,4%). Se concluye que la frecuencia viral respiratoria estuvo relacionada con la edad, estacionalidad y patología preexistente.

ABSTRACT The aim of the study was to determine the viral frequency and clinical-epidemiological characteristics in the episodes of acute respiratory infection in patients of the Instituto Nacional de Salud del Niño San Borja in Lima, the information of the episodes of patients who required at least one direct Immunofluorescence test from January 1, 2017 to December 31, 2018 was analyzed. 1153 episodes were identified in 707 patients. The median age was 1 year and 55% were male. The viral frequency was 13.4%; respiratory syncytial virus was identified in 10.7% of the episodies. The viral frequency was higher in children under 1 year of age (16.2%); in those with congenital disease respiratory (38.9%) and during the autumn (24.2%). The most common symptoms were cough (70.3%) and fever (53.4%); and the main diagnoses, viral pneumonia (31.8) and bronchiolitis (23.4%). It is concluded that the respiratory viral frequency was related to age, seasonality and pre-existing pathology.

Virus respiratorios y características clínico-epidemiológicas en los episodios de infección respiratoria aguda / Respiratory viruses and clinical- epidemiological characteristics in episodes of acute respiratory infection

RESUMEN Con el objetivo de determinar la frecuencia viral y las características clínico-epidemiológicas en los episodios de infección respiratoria aguda de pacientes del Instituto Nacional de Salud del Niño San Borja en Lima, se analizó la información de los episodios de pacientes que requirieron al menos una prueba de inmunofluorescencia directa desde el 1 de enero del 2017 al 31 de diciembre del 2018. Se identificaron 1153 episodios en 707 pacientes. La mediana de la edad fue de 1 año y el 55% fueron del sexo masculino. La frecuencia viral fue del 13,4%; el virus respiratorio sincitial se identificó en el 10,7% de los episodios. La frecuencia viral fue mayor en los menores de 1 año (16,2%); en aquellos con enfermedad congénita respiratoria (38,9%) y durante el otoño (24,2%). Los síntomas más comunes fueron tos (70,3%) y fiebre (53,4%); y los principales diagnósticos fueron neumonía viral (31,8%) y bronquiolitis (23,4%). Se concluye que la frecuencia viral respiratoria estuvo relacionada con la edad, estacionalidad y patología preexistente.

ABSTRACT The aim of the study was to determine the viral frequency and clinical-epidemiological characteristics in the episodes of acute respiratory infection in patients of the Instituto Nacional de Salud del Niño San Borja in Lima, the information of the episodes of patients who required at least one direct Immunofluorescence test from January 1, 2017 to December 31, 2018 was analyzed. 1153 episodes were identified in 707 patients. The median age was 1 year and 55% were male. The viral frequency was 13.4%; respiratory syncytial virus was identified in 10.7% of the episodies. The viral frequency was higher in children under 1 year of age (16.2%); in those with congenital disease respiratory (38.9%) and during the autumn (24.2%). The most common symptoms were cough (70.3%) and fever (53.4%); and the main diagnoses, viral pneumonia (31.8) and bronchiolitis (23.4%). It is concluded that the respiratory viral frequency was related to age, seasonality and pre-existing pathology.

Childhood pemphigus vulgaris is a challenging diagnosis

Pemphigus Vulgaris (PV) is an uncommon autoimmune and blistering mucocutaneous disease. Childhood Pemphigus Vulgaris (CPV) is a pediatric variant of PV, which affects children below 12 years, being very rare among children under 10 years of age. CPV has similar clinical, histological, and immunological features as seen in PV in adults. The mucocutaneous clinical presentation is the most common in both age groups. Vesicles and erosions arising from the disease usually cause pain. A few CPV cases have been reported in the literature. This study reports a case of an 8-year-old male patient with oral lesions since the age of 3 years, and the diagnosis of pemphigus was achieved only 2 years after the appearance of the initial lesions. CPV remains a rare disease, making the diagnosis of this clinical case a challenge due to its age of onset and clinical features presented by the patient. Therefore, dentists and physicians should know how to differentiate CPV from other bullous autoimmune diseases more common in childhood.

Detección de anticuerpos contra Neospora caninum en caninos del área urbana y rural de Cumaral, Meta-Colombia

RESUMEN Objetivo. Estimar la seroprevalencia a Neospora caninum en caninos del área urbana y rural de Cumaral, Meta y determinar algunos factores de riesgo asociados a la seropositividad. Materiales y métodos. Se efectuó un estudio transversal en 222 perros (112 perros del área urbana y 110 del área rural). El tamaño de la muestra fue calculado en el programa Epidat v. 3.1. Los sueros sanguíneos fueron analizados mediante la técnica de Inmunofluorescencia Indirecta para IgG con un kit comercial. Los análisis de frecuencias, chi-cuadrado, fueron realizados mediante el paquete estadístico SPSS v. 25.0 Resultados. La seroprevalencia general fue 36.9% (IC95%: 30.9-43.5 %). La seropositividad entre los grupos fue: urbana (38.4 %) y rural (35.5%) (p>0.05), machos (36.9%) y hembras (36.9%) (p >0.05); en cachorros (32.7%), jóvenes (40.0%) y adultos (37.4%) (p>0.05), en contacto con predios pecuarios (40.7%) y sin contacto (35.2%) (p>0.05). Conclusiones. La seroprevalencia observada fue alta en las dos poblaciones analizadas y sugiere que los caninos han estado en contacto con el parásito, posiblemente por diferentes fuentes de infección que requieren ser estudiadas posteriormente.

ABSTRACT Objective. To estimate the seroprevalence to Neospora caninum in canines of the urban and rural area of Cumaral, Meta and determine some risk factors associated with seropositivity. Materials and methods. A cross-sectional study was carried out in 222 dogs (112 dogs from the urban area and 110 dogs from the rural area), the sample size was calculated by using Epidat v program. 3.1. The sera were analyzed using the Indirect Immunofluorescence technique for IgG with a commercial kit. Frequency analyzes by chi-square of independence were performed in SPSS v. 25.0 Results. The general seroprevalence was 36.9% (95% CI: 30.9-43.5%). The seropositivity between the groups was: urban (38.4%) and rural (35.5%) (p>0.05), males (36.9%) and females (36.9%) (p>0.05); in puppies (32.7%), youth (40.0%) and adults (37.4%) (p>0.05), in contact with livestock farms (40.7%) and without contact (35.2 %) (p>0.05), Conclusions. The seroprevalence observed was high in the two populations analyzed and suggests that the canines have been in contact with the parasite, possibly due to different sources of infection that need to be studied later.

Patrones diferenciales entre Leishmaniasis y chagas, empleando epimastigotes de Trypanosoma cruzi / Differential patterns between leishmaniasis and chagas disease using Trypanosoma cruzi epimastigotes

En diferentes regiones de Latinoamérica la infección por T. cruzi y Leishmania se superponen, por lo cual se reportan infecciones mixtas circulantes, debido a esto; deben realizarse pruebas diagnósticas específicas para evitar reacciones cruzadas entre estas dos patologías. OBJETIVO: determinar patrones de fluorescencia que permitan la diferenciación entre Leishmaniasis, enfermedad de Chagas e infección mixta empleando epimastigotes de T. cruzi. MÉTODOS: se empleó la técnica de Inmunofluorescencia Indirecta utilizando epimastigotes de T. cruzi (TcV autóctono) como antígeno figurado frente a un panel de muestras de suero codificados como A, B, C y D correspondientes a pacientes con infección por: Leishmaniasis (A), Infección mixta por Leishmania y Chagas(B), Enfermedad de Chagas (C) y sin ninguna de las dos infecciones (D). RESULTADOS: en los cuatro paneles de muestras se observaron diferentes patrones de intensidad de fluorescencia a nivel de membrana y núcleo de los epimastigotes de T. cruzi (TcV autóctono). CONCLUSIONES: la técnica de Inmunofluorescencia (IFI) con antígenos de epimastigotes de T. cruzi a demostrado utilidad en la diferenciación entre enfermedad de Chagas, Leishmaniasis y/o infecciones mixtas por ambos parásitos en aquellas zonas donde la coexistencia de ambas es habitual

In different regions of Latin America, infection by T. cruzi and Leishmania overlap, for which mixed circulating infections are reported, due to this; Specific diagnostic tests must be performed to avoid cross reactions between these two pathologies. OBJECTIVE: to determine fluorescence patterns that allow the differentiation between Leishmaniasis, Chagas disease and mixed infection using T. cruzi epimastigotes. METHODS: the Indirect Immunofluorescence technique was used using epimastigotes of T. cruzi (autochthonous TcV) as figurative antigen against a panel of serum samples coded as A, B, C and D corresponding to patients with infection by: Leishmaniasis (A) , Mixed infection by Leishmania and Chagas (B), Chagas disease (C) and without either of the two infections (D). RESULTS: in the four sample panels, different patterns of fluorescence intensity were observed at the membrane and nucleus level of the epimastigotes of T. cruzi (autochthonous TcV). CCONCLUSIONS: the Immunofluorescence technique (IFI) with T. cruzi epimastigote antigens has proven useful in differentiating between Chagas disease, Leishmaniasis and / or mixed infections by both parasites in areas where the coexistence of both is common.

Aislamiento y caracterización de una cepa temprana de SARS-CoV-2 durante la epidemia de 2020 en Medellín, Colombia / Isolation and characterization of an early SARS-CoV-2 isolate from the 2020 epidemic in Medellín, Colombia

Introducción. El nuevo coronavirus causante de un brote de enfermedad respiratoria aguda en China en diciembre de 2019 se identificó como SARS-CoV-2. La enfermedad, denominada COVID-19, fue declarada pandemia por la Organización Mundial de la Salud (OMS). El primer caso de COVID-19 en Colombia se reportó el 6 de marzo de 2020; en este estudio se caracterizó un aislamiento temprano del virus SARS-CoV-2 de una muestra recolectada en abril de 2020. Objetivos. Describir y caracterizar una cepa temprana a partir de un aislamiento de SARS-CoV-2 durante la pandemia en Colombia. Materiales y métodos. Se obtuvo una muestra de un paciente con COVID-19 confirmada por qRT-PCR; la muestra fue inoculada en diferentes líneas celulares hasta la aparición del efecto citopático. Para confirmar la presencia de SARS-CoV-2 en el cultivo, se utilizó la qRT-PCR a partir de los sobrenadantes, la inmunofluorescencia indirecta (IFI) en células Vero-E6, así como microscopía electrónica y secuenciación de nueva generación (next-generation sequencing). Resultados. Se confirmó el aislamiento de SARS-CoV-2 en células Vero-E6 por la aparición del efecto citopático tres días después de la infección, así como mediante la qRT-PCR y la IFI positiva con suero de paciente convaleciente positivo para SARS-CoV-2. Además, en las imágenes de microscopía electrónica de trasmisión y de barrido de células infectadas se observaron estructuras compatibles con viriones de SARS-CoV-2. Por último, se obtuvo la secuencia completa del genoma, lo que permitió clasificar el aislamiento como linaje B.1.5. Conclusiones. La evidencia presentada en este artículo permite confirmar el primer aislamiento de SARS-CoV-2 en Colombia. Además, muestra que esta cepa se comporta en cultivo celular de manera similar a lo reportado en la literatura para otros aislamientos y que su composición genética está acorde con la variante predominante en el mundo. Finalmente, se resalta la importancia que tiene el aislamiento viral para la detección de anticuerpos, para la caracterización genotípica y fenotípica de la cepa y para probar compuestos con potencial antiviral.

Introduction: SARS-CoV-2 has been identified as the new coronavirus causing an outbreak of acute respiratory disease in China in December, 2019. This disease, currently named COVID-19, has been declared as a pandemic by the World Health Organization (WHO). The first case of COVID-19 in Colombia was reported on March 6, 2020. Here we characterize an early SARS-CoV-2 isolate from the pandemic recovered in April, 2020. Objective: To describe the isolation and characterization of an early SARS-CoV-2 isolate from the epidemic in Colombia. Materials and methods: A nasopharyngeal specimen from a COVID-19 positive patient was inoculated on different cell lines. To confirm the presence of SARS-CoV-2 on cultures we used qRT-PCR, indirect immunofluorescence assay, transmission and scanning electron microscopy, and next-generation sequencing. Results: We determined the isolation of SARS-CoV-2 in Vero-E6 cells by the appearance of the cytopathic effect three days post-infection and confirmed it by the positive results in the qRT-PCR and the immunofluorescence with convalescent serum. Transmission and scanning electron microscopy images obtained from infected cells showed the presence of structures compatible with SARS-CoV-2. Finally, a complete genome sequence obtained by next-generation sequencing allowed classifying the isolate as B.1.5 lineage. Conclusion: The evidence presented in this article confirms the first isolation of SARS-CoV-2 in Colombia. In addition, it shows that this strain behaves in cell culture in a similar way to that reported in the literature for other isolates and that its genetic composition is consistent with the predominant variant in the world. Finally, points out the importance of viral isolation for the detection of neutralizing antibodies, for the genotypic and phenotypic characterization of the strain and for testing compounds with antiviral potential.

Anticuerpos antimitocondriales y anticuerpos contra antígenos extraíbles del núcleo en pacientes con cirrosis biliar primaria / Antimitochondrial Antibodies and antibodies against extractable nucleus antigens in patients with primary biliary cirrhosis

Resumen Objetivo: Determinar la frecuencia de anticuerpos antimitocondriales y de anticuerpos contra antígenos extraíbles del núcleo en pacientes con cirrosis biliar primaria. Material y métodos: Estudio de tipo cuantitativo, observacional y transversal, realizado en el Servicio de Inmunología del Hospital Nacional Arzobispo Loayza entre enero 2018 y marzo 2019. Se revisaron las historias clínicas de 30 pacientes con características presuntivas de cirrosis biliar primaria; para la detección de los anticuerpos antinucleares y anticuerpos antimitocondriales se empleó el kit inmunológico en sangre y observación con microscopio de inmunofluorescencia a 40X y para la detección de los anticuerpos contra antígenos extraíbles del núcleo se empleó el método Immunoblot. Resultados: Se estudiaron 30 pacientes con cirrosis biliar primaria, 20 fueron de sexo femenino (66,7%). El patrón de tinción más frecuente fue el citoplasmático moteado reticular en 17(56,7%), seguido del patrón citoplasmático moteado reticular y patrón moteado en 7(23,3%) pacientes, y en menor frecuencia el patrón citoplasmático moteado reticular y patrón centromérico. Nueve (42,9%) pacientes con cirrosis biliar primaria tenían anti-M2. Se demostró mayor frecuencia, 21(70%) de los pacientes con cirrosis biliar primaria tenían anticuerpos antimitocondriales. Conclusiones: Se encontró alta frecuencia de patrón citoplasmático moteado reticular en pacientes con cirrosis biliar primaria, se demostró asociación significativa con los anti-M2 y anticuerpos antimitocondriales.

Summary Objective: To determine the frequency of antimitochondrial antibodies and antibodies against extractable nucleus antigens in patients with primary biliary cirrhosis. Methods : A quantitative, observational and cross-sectional study was carried out at the Immunology Service of the Arzobispo Loayza National Hospital between January 2018 and March 2019. The medical records of 30 patients with presumptive characteristics of primary biliary cirrhosis were reviewed; for the detection of the antinuclear antibodies and antimitochondrial antibodies, the immunological kit was used in blood and observation with a 40X immunofluorescence microscope, and the Immunoblot method was used for the detection of the antibodies against extractable nucleus antigens. Results: Thirty patients with primary biliary cirrhosis disease were studied, 20 were female (66.7%). The most frequent staining pattern was the reticular mottled cytoplasmic in 17 (56.7%), followed by the reticular mottled cytoplasmic pattern and mottled pattern in 7 (23.3%) patients, and less frequently the reticular mottled cytoplasmic pattern and centromeric. Nine (42.9%) patients with primary biliary cirrhosis had anti-M2. In the present investigation, a higher frequency was demonstrated, 21 (70%) of the patients with primary biliary cirrhosis had antimitochondrial antibodies. Conclusions: A high frequency of reticular mottled cytoplasmic pattern was found in patients with primary biliary cirrhosis; a significant association with anti-M2 and antimitochondrial antibodies was demonstrated.

Clinical significance of glomerular IgG4 deposition in primary membranous nephropathy / 中华肾脏病杂志

Objective@#To analyze the distribution of glomerular immunofluorescence IgG4 subtypes in primary membranous nephropathy, and to explore the relationship between IgG4 deposit intensity and renal pathology, clinical manifestations and prognosis.@*Methods@#All the patients of biopsy-proven primary membranous nephropathy with IgG staining and at least one IgG subtype staining 1+ or higher on capillary loops from September 2015 to April 2017 were retrospectively enrolled. The distribution of IgG4 deposits were analyzed, and the relationship between IgG4 positive intensity and clinical manifestations, pathological indexes and clinical remission was investigated.@*Results@#A total of 250 cases were enrolled, including 157 males (62.8%) and 93 females (37.2%), and age was (54.4 ± 14.6) years. There were 40 patients in IgG4-negative group, and 210 patients in IgG4-positive group. The IgG4-positive group was divided into subgroups as 114 cases of the mild positive subgroup (1+) and 62 cases of the moderate positive subgroup (2+), and 34 cases of the strong positive subgroup (3+, 4+). The IgG4-positive group had higher 24-hour urine protein and higher positive rate of phospholipase A2 receptor staining than those in the negative group (both P<0.05), while the strong positive subgroup had lower serum albumin and higher IgG1 staining than those in the mild positive subgroup (both P<0.05). There was no difference in the ratio of glomerular sclerosis, tubular atrophy, IgG2, IgG3 or other immunofluorescence between the groups. After a median follow-up of 180(122, 209) days, 32 individuals were lost to follow-up. Among the rest 218 patients, 45 patients (20.6%) got complete remission, 104 patients (47.7%) got partial remission, and 69 patients (31.7%) showed no response. For no response as the outcome event, multivariate Cox regression analysis showed that higher IgG4 staining intensity (HR=1.371, 95%CI 1.068-1.759, P=0.013), male (HR=1.818, 95%CI 1.028-3.214, P=0.040), higher 24-hour urine protein level (HR=1.108, 95%CI 1.003-1.225, P=0.043) were independent risk factors for disease remission.@*Conclusions@#The glomerular IgG4 positivity and intensity are related to the severity of primary membranous nephropathy. The glomerular IgG4 deposit degree may be an effective prognostic marker for the treatment response of primary membranous nephropathy.

Performance evaluation of an indirect immunofluorescence kit for the serological diagnosis of dengue / Avaliação do desempenho de kit de imunofluorescência indireta para o diagnóstico sorológico de dengue

ABSTRACT Objective: To evaluate the performance of indirect immunofluorescence for serological diagnosis of dengue virus in a population with high prevalence of arboviruses. Methods: Two-hundred serum samples from patients with clinical suspicion of dengue fever were tested by immunoenzymatic and indirect immunofluorescence assay BIOCHIP® mosaic. Specificity, sensitivity and Kappa coefficient were calculated. Discordant samples were tested by polymerase chain reaction for confirmation. Results: Of the 200 samples, 20% were positive and 80% negative for anti-dengue virus IgM antibodies in the immunoenzymatic test. Of the 40 positives, 25% were negative in indirect immunofluorescence. Of these ten discordant results, only 20% were also negative in the polymerase chain reaction (PCR). Of the 160 negatives in the immunoenzymatic test, 5% were positive in indirect immunofluorescence. Of these nine discordant results, 33% were positive in the PCR. The Kappa coefficient was 0.7 (0.572-0.829). Sensitivity and specificity of indirect immunofluorescence were respectively 75% and 94%. For anti-dengue virus IgG antibodies, of the 200 samples, 15.5% were positive and 84.5% were negative in the immunoenzymatic test. Of the 31 positives, 12.9% were negative in indirect immunofluorescence. Of these four discordant results, 25% were negative in the PCR. Of the 169 negatives, 8% were positive in indirect immunofluorescence. Of these 14 discordant results, 64% were also positive in the PCR. The Kappa coefficient was 0.695 (0.563-0.83). Sensitivity and specificity of indirect immunofluorescence were 87.1% and 91.7%, respectively. Conclusion: For diagnosis of acute infection, the immunoenzymatic test is enough, and the use of additional methods is not warranted. Replacing the immunoenzymatic test by indirect immunofluorescence would compromise the sensitivity for IgM. However, indirect immunofluorescence can distinguish three arboviruses simultaneously, an advantage during concomitant epidemics.

RESUMO Objetivo: Avaliar o desempenho da imunofluorescência indireta no diagnóstico sorológico de dengue em uma população com alta prevalência de arboviroses. Métodos: Duzentas amostras de soro de pacientes com suspeita clínica de dengue foram testadas por ensaio imunoenzimático e imunofluorescência indireta mosaico BIOCHIP®. Foram calculados especificidade, sensibilidade e coeficiente Kappa. Nas amostras discordantes, realizou-se reação em cadeia da polimerase como método confirmatório. Resultados: Das 200 amostras, 20% foram positivas e 80% negativas para IgM antivírus da dengue no ensaio imunoenzimático. Das 40 positivas, 25% foram negativas na imunofluorescência indireta. Destas dez negativas, apenas 20% eram também negativas na reação em cadeia da polimerase. Das 160 negativas no ensaio imunoenzimático, 5% foram positivas na imunofluorescência indireta. Por fim, dentre as nove discordantes, 33% tiveram vírus da dengue detectado na reação em cadeia da polimerase. O coeficiente Kappa foi 0,70 (0,57-0,82). Sensibilidade e especificidade por imunofluorescência indireta foram, respectivamente, 75% e 94%. Para IgG antivírus da dengue, de 200 amostras, 15,5% foram positivas e 84,5% negativas no ensaio imunoenzimático. Das 31 positivas, 12,9% foram negativas na imunofluorescência indireta. Destas quatro discordantes, 25% apresentaram vírus da dengue não detectado na reação em cadeia da polimerase. Das 169 negativas, 8% foram positivas na imunofluorescência indireta. Destas, 64% foram positivas também na reação em cadeia da polimerase. O coeficiente Kappa foi 0,695 (0,56-0,83). Sensibilidade e a especificidade por imunofluorescência indireta foram, respectivamente, 87,1% e 91,7%. Conclusão: Ensaio imunoenzimático seria suficiente para diagnóstico sorológico de infecção aguda, não justificando a incorporação da imunofluorescência indireta. Substituir ensaio imunoenzimático pela imunofluorescência indireta poderia comprometer a sensibilidade para IgM. Contudo, a imunofluorescência indireta auxilia diferenciar três arboviroses simultaneamente, sendo vantajoso em epidemias concomitantes.

Comparison between enzyme-linked immunosorbent assay and indirect immunofluorescence for detection of antineutrophil cytoplasmic antibodies / Comparação entre os métodos de ensaio imunoenzimático e imunoflurescência indireta para a pesquisa de anticorpos anticitoplasma de neutrófilos

ABSTRACT Objective To evaluate the performance of enzyme-linked immunosorbent assay and indirect immunofluorescence methods for the detection of antineutrophil cytoplasmic antibodies in a routine clinical laboratory setting. Methods A total of 227 samples were tested by indirect immunofluorescence and enzyme-linked immunosorbent assay with antigen specificity for antiproteinase 3 and antimyeloperoxidase. The proportions of positive samples were compared by McNemar hypotheses and agreement was described by Cohen's Kappa coefficient. Results The agreement of the tests was 96.5%, and the Kappa coefficient obtained was 0.70 (95%CI: 0.50-0.90; p<0.001). Considering indirect immunofluorescence as the gold standard, the sensitivity of the enzyme-linked immunosorbent assay was 0.62 and the specificity was 0.99, with diagnostic accuracy in 96% of cases. Some samples were negative in enzyme-linked immunosorbent assay and positive in indirect immunofluorescence. This situation occurred in all immunofluorescence patterns, but particularly in atypical patterns. Two samples with antiproteinase 3 positivity were considered negative in indirect immunofluorescence. Conclusion The enzyme-linked immunosorbent assay had high specificity but lower sensitivity. The performance of indirect immunofluorescence increases diagnostic sensitivity, while the search for antiproteinase 3 by enzyme-linked immunosorbent assay may also add diagnostic power.

RESUMO Objetivo Avaliar o desempenho das metodologias de ensaio imunoenzimático e imunofluorescência indireta para a detecção de anticorpos anticitoplasma de neutrófilos em um contexto de laboratório clínico de rotina. Métodos Foram testadas 227 amostras pelas metodologias de imunofluorescência indireta e ensaio imunoenzimático com especificidades para anticorpos antiproteinase-3 e antimieloperoxidase. As proporções de amostras positivas foram comparadas por hipóteses de McNemar, e a concordância foi descrita pelo coeficiente Kappa de Cohen. Resultados A concordância dos testes foi 96,5%, e o coeficiente Kappa obtido foi 0,70 (IC95%: 0,50-0,90; p<0,001). Utilizando a imunofluorescência indireta como padrão-ouro, a sensibilidade do ensaio imunoenzimático foi de 0,62 e a especificidade, 0,99, com acurácia diagnóstica em 96% dos casos. Algumas amostras apresentaram resultados negativos por ensaio imunoenzimático e positivos por imunofluorescência. Isso ocorreu em amostras com vários padrões de fluorescência, mas particularmente nos casos com padrões atípicos. Duas amostras com positividade antiproteinase 3 foram consideradas negativas por imunofluorescência. Conclusão Os métodos de ensaio imunoenzimático tiveram alta especificidade, mas sensibilidade inferior. A realização da imunofluorescência indireta aumenta a sensibilidade diagnóstica, ao mesmo tempo que a pesquisa de antiproteinase 3 por ensaio imunoenzimático também pode agregar poder diagnóstico.

Infectious endocarditis by Bartonella species: report of two cases / Endocarditis infecciosa por Bartonella: descripción de dos casos en Chile

ABSTRACT Infectious endocarditis (IE) by Bartonella species is an emerging problem worldwide. We report two cases of native valve Bartonella-associated IE events, both affecting adult male patients with a history of alcohol abuse and a low socioeconomic status. Admissions were due to pancytopenia and bleeding in one case and embolic stroke in the other. Blood cultures were negative and IgG indirect immunofluorescence assays (IFA) were positive for B. henselae/B. quintana in high titers (1/16,384-1/16,384, and 1/32,768 -1/16,384, respectively). Cases were classified as definitive IE events according to modified Duke criteria due to the presence of valve vegetations with at least three minor criteria. One patient required aortic mechanical valve replacement and survived, and the other died after a massive hemorrhagic transformation of his stroke. PCR amplification and sequencing of the 16S ribosomal bacterial DNA from a valve tissue sample obtained at surgery in the patient who survived, confirmed B. quintana as the etiological agent. Bartonella-associated IE is an emerging problem in Chile, present in disadvantaged populations. It should be suspected in patients with culture-negative IE. IFA does not discriminate between B. henselae and B. quintana infection, but high titers suggest IE. Complementary PCR techniques may help to elucidate the final causative agent.

La endocarditis infecciosa(EI) asociada a Bartonella es un problema emergente a nivel mundial. Publicamos los 2 primeros casos de EI en válvula nativa asociados a Bartonella en Chile, los que afectaron a pacientes masculinos con historia de consumo de alcohol y bajos ingresos. La hospitalización fue provocada por pancitopenia y hemorragias en un caso y por un evento cerebrovascular en el otro. Se solicitó serología para Bartonella por inmunofluorescencia indirecta (IFI) para ampliar el estudio ante hemocultivos negativos y en ambos casos se reportaron resultados intensamente positivos para B. henselae y B. quintana1/16.384-1/16.384 y 1/32.768 -1/16.384, respectivamente). Los casos se clasificaron como eventos definitivos de EI según los criterios modificados de Duke debido a la presencia de vegetaciones valvulares con al menos 3 criterios menores. Un paciente requirió reemplazo valvular aórtico y sobrevivió, y el otro falleció tras una transformación hemorrágica masiva del infarto cerebral. La amplificación del ADN ribosomal 16S por RCP y posterior secuenciación de una muestra de tejido valvular confirmó la presencia de B. quintana. La EI por Bartonella sp. es un problema emergente en Chile, probablemente asociada a poblaciones desfavorecidas, la que debe ser sospechada en pacientes con cultivos negativos. La IFI no permite discriminar infecciones por B. henselae o B. quintana pero los títulos altos sugieren EI. Técnicas complementarias por RCP pueden ayudar a dilucidar el diagnóstico.